Process and apparatus for etching an image within a solid article

Abstract

An apparatus and process for etching an image within a solid article including the steps of focusing a laser to a focal point within the article and positioning the article with respect to the focal point. The laser is fired so that local disruption occurs within the article to form the image within the article.

What is claimed is: 
     
       1. An apparatus for etching an image within a solid article, comprising: an impulse laser for generating a laser emission having a power rating of 50 Mjoules and a pulse length of 10 nsec and a pulse frequency of 1 Hertz;   a focusing lens located at an operative distance from said laser to focus the laser emission to a focal point within the article;   means for positioning the article with respect to the focal point including   (a) a motor driven support bench for receiving and supporting the article;   (b) a threaded nut attached to said support bench; and   (c) at least one step motor including a threaded rod cooperatively sized to engage said threaded nut, whereby said at least one step motor rotates said threaded rod to move said threaded nut and said support bench linearly along said threaded rod axis;   control means coupled to said impulse laser and said positioning means for firing said laser so that a local disruption having a lower translucence than the article occurs at the focal point within the article, without affecting an area surrounding the focal point, to form the image within the article.